小编Woj*_*Maj的帖子

#container {
  display: flex;
  max-width: 80vw;
  max-height: 100px;
  flex-direction: column;
}

#content {
  overflow-y: auto;
}

/* styling - ignore */
#container {
  border: 2px solid black;
  margin-bottom: 1em;
}
#header {
  background-color: rgb(245, 245, 245);
  padding: 10px;
}
#content {
  background-color: rgb(255, 255, 255);
  padding: 0 10px;
}

<div id="container">
  <div id="header">Header</div>
  <div id="content">
    <p>Everything works as supposed to, move along</p>
  </div>
</div>

<div id="container">
  <div id="header">Header</div>
  <div id="content">
    <p>Very long content</p>
    <p>Very long content</p>
    <p>Very long content</p> …